A robust turn-on luminescent MOF probe with redox center and rare RE4 cluster for highly sensitive detection of captopril

Sensitive detection of captopril (CP) is necessary from a point of physiological, but the nature of no luminescence response and low ultraviolet absorption make it difficult in luminescent technology. Here, a series of novel RE (III)-MOFs featuring the rare tetranuclear RE4(mu(3)-OH)(2)(mu(2)-COO)(8) cluster, namely, {[RE4(tbia)(4)(NO3)(2)(OH)(2)(H2O)(4)]center dot CH3CN}n (RE-tbia, RE3+ = Sm3+ (1), Eu3+ (2), Gd3+ (3), Tb3+ (4), Dy3+ (5), Er3+ (6), Yb3+ (7), H(2)tbia = 5-((4'-(triazol-1-yl)benzyl)oxy)isophthalic acid), have been successfully synthesized via a solvothermal reaction. The as-prepared Tb-tbia shows high water stability, thermal stability and excellent luminescence property through an antenna effect due to the unique RE4 cluster. Considering the sulfhydryl groups in the CP, a redox center Ce(IV) was introduced to construct a stable luminescent probe Ce0.2Tb0.8-tbia for turn-on luminescence detecting CP molecules. The reactive Ce4+ redox centers not only optimize the lumines-cence intensity of Tb-tbia, but also act as redox centers and react with CP to form captopril-disulfide (CP-DS). Therefore, the Ce0.2Tb0.8-tbia possesses a low detection limit of 64.6 nM for CP in the aqueous solution, showing a high sensitivity and application perspective.